For instance, the properties of IFontDisp ( font ) type has variables like: Name, Size, and so on. Changing the ShowVariables at runtime executes a refresh of the browsed control. If you want to filter the object properties that has some special flags you can use Flags property of Property object. 

Here's a sample that shows how to include only hidden members:

Private Sub PropertiesList1_IncludeProperty(ByVal Property As EXPROPERTIESLISTLibCtl.IProperty, Cancel As Boolean)
    Cancel = Not (Property.Flags And &H40) = &H40
End Sub